Of course not. A minority of people use most of the world’s energy and other resources. Not only are their needs met, but they have many luxuries. Many other people lack resources. Many don’t have enough to eat or live, with the threat of hunger. Many also do not have safe, clean water. Some people live in crowded, run-down housing. Some people live in mansions.

Overpopulation?

Overpopulation
takes place when the number of organisms exceeds the carrying capacity of the region. What is the carrying capacity of Earth for humans? Are seven billion people the human carrying capacity? Nine billion? We don't know yet.

It seems that we have increased the carrying capacity of the planet for humans. We have done this with agriculture and fossil fuels and improvements in health care. Have we now exceeded Earth's carrying capacity (
Figure
below
)? Are humans on Earth experiencing overpopulation?

Manhattan, one part of New York City, is one of the most heavily populated regions in the world.

There is not yet an answer to that question. So far, many of us have skated along without much trouble. But since we depend on resources that are non-renewable, the answer could well be yes.

There is evidence that there are too many of us; that the large population is becoming too high. That’s because we are harming the environment. Some of the harmful effects of a high human population are:

Supplying all those people with energy creates a lot of pollution. For example, huge oil spills have killed millions of living things.

Fossil fuels and other resources are being used up. We may run out of oil by the mid-2000s. Many other resources will run out sooner or later.

People are killing too many animals for food. For example, some of the best fishing grounds in the oceans have almost no fish left.

People have destroyed many habitats. For example, they’ve drained millions of acres of wetlands. Wetlands have a great diversity of species. As wetlands shrink, species go extinct.

People have introduced
invasive species
- species originally from a different area—to invade new habitats. The introduction can be intentional or accidental. Often, the aliens have no natural enemies in their new home. They may drive native species extinct. In the mid-1900s, Australian tree snakes invaded Guam and other islands in the Pacific. The snakes stowed away on boats and planes. Tree snakes had no natural enemies on the islands so their population exploded. The snakes have caused the extinction of nine of the eleven native bird species on Guam (
Figure
below
).

A brown tree snake.

People themselves are also affected by the large size of the human population. Some people have a lot; some have very little. Many people refer to the abundance of luxury items in some people’s lives as
over-consumption
. People in developed nations use 32 times more resources than people in the developing countries of the world. The symbol of this is CO
2
emissions, which are a waste product from fossil fuel burning. Populations that burn the most fossil fuels have a high standard of living.

CO
2
emissions tell which countries are using the most fossil fuels.

Summary

Supporting 7 billion people is taking an environmental toll on the planet.

Pollution, habitat destruction, and invasive species are a few of the problems caused by the high population.

Over-consumption means that some people use a much larger amount of the resources than others.